There is a need in telecommunication systems for the possibility of being able to send information concerning costs charged to a subscriber who is debited for an established connection. The line circuit of the subscriber includes a circuit which generates metering pulses which can be transferred on the subscriber line from the telecommunication exchange to which the subscriber is connected. A presentation unit installed with the subscriber is activated by the metering pulses and discloses the cost incurred by the connection. The metering pulses are transferred together with other information on the subscriber line and it is essential that this information is not influenced in any way. It is therefore important that the amplitude of the metering pulse will increase and decrease relatively slowly and it is also important that the metering pulses have the correct amplitude so that a correct subscriber debit is recorded. A circuit which generates this type of metering pulse is described in the Swedish Patent Specification No. 8502130-1. This circuit has a multiplier in which a sinusoidal alternating voltage is multiplied with a limiting voltage which determines the amplitude of the metering pulse. The alternating voltage has a frequency of either 12 KHz or 16 KHz. The limiting voltage, which is generated in a generator circuit, rises linearly to a desired amplitude in a first part of the pulse, remains constant over a second part of the pulse and decreases linearly in a third part of said pulse. As the pulse is generated in the multiplier, the pulse is supplied to the subscriber line and registered on the subscriber presentation unit. The pulse is also coupled back through a feedback circuit via a highpass filter through which only the sinusoidal alternating voltage passes. The filtered pulse is rectified and compared with a reference voltage in a comparator, the output signal of which is used to control the generator circuit. The generator circuit has a capacitor and current generator which charges and discharges the capacitor. A control signal generated in a telephone exchange resets a first switch in the generator circuit and connects the one current generator to the capacitor. The voltage over the capacitor, which is the limiting voltage, rises linearly with time and generates the first part of the metering pulse. When the amplitude of the metering pulse is the same as the reference voltage, the comparator opens the first switch. The capacitor voltage therefore remains substantially constant and forms the second part of the metering pulse. The control signal from the telephone exchange closes a second switch in the generator circuit and connects the second current generator to the capacitor. The capacitor is discharged and delivers a linearly decreasing voltage which forms the third part of the metering pulse. One drawback with the aforedescribed circuit is that the amplitude of the metering pulse can vary in response to variations in the subscriber line impedance or in response to variations in amplitude of the sinusoidal alternating voltage. There is thus a risk that a wrong charge will be registered on the subscriber presentation unit.